Multi-hulled craft such as trimarans and catamarans, because of their relatively wide overall beam, have a disadvantage in that they are often too wide for transportation by road and also for berthing in marina pens and for manoeuvring in crowded anchorages. To overcome this disadvantage, especially in trimarans, many proposals have been devised to enable the floats to be selectively movable from an operative position where they are spaced outwardly from the main hull for maximum stability, to an inoperative position wherein the floats are moved inwards to lie adjacent the main hull to reduce the overall beam of the craft.
While this invention applies to catamarans and other two-hulled craft, it is particularly applicable to trimarans in which the accommodation is arranged in the central hull while the outer floats serve the main purpose of providing stability. In modern trimarans, the trend is to increased overall beam, therefore the loads on the beams interconnecting the floats with the main hull are increased.
With this trend to increased beams, floats of smaller proportions are being used and the floats are being kept as light as possible so as not to detract from the manoeuvrability of the trimaran. Thus, the floats are lightly constructed and are susceptible to damage, especially in confined areas where other craft are manoeuvring and collisions may occur. Additionally, because of their wide beam, multi-hulled boats which are built remote from launching sites are difficult to transport to their launching site, and it is advantageous if the floats can be removed or moved inwards to reduce the overall beam of the craft to enable it to be transported by normal road trailer.
To date, many proposals have been made to enable the overall beam of multi-hulled boats to be reduced. In some instances, the floats are simply bolted onto connecting beams and the craft may be dismantled for transportation. However, the floats must be reassembled before the boat is launched.
In another configuration, known as the "swing wing" configuration which has been used extensively on trimarans, the beams connecting the outrigger floats to the main hull are connected pivotally at their inner and outer ends to the main hull and floats respectively for pivotal movement about substantially parallel vertical axes. Two such beams are used per side and arranged to form a parallelogram arrangement so that the distance between the float and the main hull may be varied by pivoting the beams and there being provided means to retain the floats in their selected position.
While this method is reasonably successful, it imposes extremely high loads on the pivotal connections, especially those at the main hull. Furthermore, as these pivotal connections are exposed in a very corrosive sea-air atmosphere, their life expectancy and predictable serviceability leave much to be desired. Accordingly, there exists a great deal of resistance to such configurations because of the unavoidable weakness of the system. It will be appreciated that the ultimate loads imposed on the pivotal joints when multi-hulled craft are caught out in unusually rough conditions can be extremely high and failure of the float connections would have serious consequences. Thus, at present, most multi-hulled craft are built as a rigid unit, with their owners accepting the above disadvantages, mainly because of the lack of a suitable alternative.
Other arrangements for retracting floats of a trimaran have been proposed, but these suffer from the main disadvantage of an inherent weakness of hinged joints which are subjected to a corrosive atmosphere. Also, the prior proposals which simply arrange a pivot assembly in the connecting beams require the trimaran to be raised above the supporting surface, whether it be the water on which the boat floats or the ground, by a trailer or the like to enable the floats to swing down to their folded positions, because the floats in their folded position are disposed below the water line of the boat. If such craft have a very wide beam the floats in their folded attitude may extend below the bottom of the main hull. Another disadvantage with both fixed pivot arrangements, that is fixed pivots about vertical or horizontal axes, is that with fixed horizontal pivot axes folding of the floats increases the overall depth of the berth and with fixed vertical pivot axes, the overall length of the boat is increased because when the floats are swung to their folded attitude, the floats extend past the end of the main hull. Both such increases are a distinct disadvantage when trailing such craft.
It is, therefore, an object of this invention to provide a float connection assembly which will overcome the above and other disadvantages and which will be reliable and efficient in operation. In particular, it is an object of this invention to provide such connection assemblies in which the beams connecting the floats when in their operative disposition do not transfer the load only through hinged joints. Another object of this invention is to provide a float connection assembly for an outrigger type craft which will enable an outrigger float to be moved from its operative spaced position to its inoperative retracted position while the craft is floating and remains on an even keel. Other objects and advantages of the invention will become apparent from the following description.